Typedef结构无法转换为指针

Question

I've seen this question in multiple posts but I have yet to find one that has a good explanation for me. Im trying to create a linked list but the struct nor the functions cant be called without getting the error cannot cast to a pointer. Its really bugging me. Any help would be appreciated on how to get this working right. Heres some of the code below thats the issue.

typedef struct node
{
    void *data;
    struct node *next;
} node;

node *head = NULL;

node* create(void *data, node *next)
{
    node *new_node = (node*)malloc(sizeof(node));
    if(new_node == NULL)
    {
        exit(0);
    }else{

        new_node->data = data;
        new_node->next = next;
        return new_node;
    }

}

node* prepend(node *head, void *data)
{
    node *new_node = create(data,head);
    head = new_node;
    return head;
}


void preload_adz(int adz_fd)
{
    struct adz adz_info;
    char adz_data[40];
    char adz_text[38];
    int adz_delay;
    char adz_delayS[2];

    read(adz_fd,adz_data,40);
    strncpy(adz_text,adz_data + 2,40-2);
    sprintf(adz_delayS, "%c%c",adz_data[0],adz_data[1]);
    adz_delay = atoi(adz_delayS);

    adz_info.delay = adz_delay;
    strncpy(adz_info.text,adz_text,38);

    head = prepend(head, (void*)adz_info); //<---This line throws the error

    while(read(adz_fd,adz_data,40) > 0)
    {

    }
}

Answer 1

struct adz adz_info;

...

head = prepend(head, (void*)adz_info); //<---This line throws the error

The problem here is adz_info is not a pointer, it's the actual struct on the stack. Passing adz_info into a function will copy the struct.

You need a pointer to that struct. Use & to get its address. Once you have the pointer, you don't need to cast it to void pointer, that cast is automatic.

head = prepend(head, &adz_info);

Note that casting is a bookkeeping thing. Casting to void * doesn't turn a struct into a pointer, it says "compiler, ignore the declared type of this variable and just trust me that this is a void pointer".